The present invention relates generally to flow monitoring systems in a sewer network. More particularly, the present invention relates to a method and system for determining the time corresponding to the flow of a fluid from one point in a network to another without requiring detailed information about the system, such as the distance between the two points or the number or character of sources between the points.
Tools for the accurate measurement of flow in a sewer network are an important resource for managers, mechanics, engineers, and regulators of municipal and industrial sewer networks. Accurate measurements of flow between points, and an understanding of what flow is expected to occur at a downstream point based on upstream conditions, can help determinexe2x80x94and to predictxe2x80x94when network problems such as leaks, breaks, clogs and other blockages and overflows may occur. They can also help system engineers and designers understand when additional capacity must be built into the system, as well as to help them better manage a network with its existing capacity.
One key parameter that is measured in a sewer network is the net flow between two or more points. At a basic level, the volume of flow at a downstream location minus the volume of flow at an upstream location is considered to be the net flow between the two locations. The downstream location volume is typically higher than that of the upstream location under normal conditions, as discharge sources, rainwater inflow and infiltration, and/or other sources may introduce wastewater into the network between the upstream and downstream locations. If the net flow between the two locations decreases below what is expected, or if net flow becomes negative, the network manager should investigate to determine whether a leak, break, clog, or overflow is occurring.
However, the above-described general calculation of net flow does not consider that it takes time for a particular flow element to travel from the upstream location to the downstream location, nor does it consider that such time may vary. Thus, because of the xe2x80x9ctravel time,xe2x80x9d by the time that a flow reaches a downstream location from an upstream location, the conditions at the upstream location may have become significantly different due to changes in input volumes, changes in weather conditions, or any number of conditions. Thus, the traditional way of calculating net flow is not desirable because it does not account for travel time or variations in travel time.
Sewer network managers have tried to compensate for the above-described problem in two ways. The first way is to use a larger number of monitoring points in the network, so that conditions are not likely to significantly change during the time that it takes wastewater to flow from one monitor to the next. However, flow monitors can be very expensive to purchase and costly to maintain. Thus, this solution is not desirable because it is not cost-effective, and it is often cost-prohibitive. In addition, the solution still does not account for the travel time between the monitors that are installed.
The second way is to perform detailed modeling of travel time, based on volumes of network design specifications and flow data. Such modeling exercises are time-consuming, costly, and only provide a snapshot of an anticipated travel time that matches the conditions under which the modeling occurred.
Thus, if a method and system for determining travel time in a sewer network were available that could determine the travel time in real time, using a small number of monitors and relatively little input data, significant cost savings would result, and sewer network managers would be better able to manage, predict conditions, anticipate design requirements, and respond to problems in their networks.
Accordingly, it is desirable to provide an improved method and system for analyzing flow in a sewer network that includes the real-time derivation of the time that it takes for a flow to travel between points in the network.
It is therefore a feature and advantage of the present invention to provide an improved method and system for analyzing flow in a sewer network that includes the real-time derivation of the time that it takes for a flow to travel between points in the network.
In accordance with a preferred embodiment of the present invention, a method of analyzing flow of a substance in a sewer network includes the steps of collecting first data representative of a first flow velocity of a substance at a first location, as well as collecting second data representative a second flow velocity of the substance at a second location. In a preferred embodiment, the method also includes transmitting, via at least one communications link, the first data and second data to a processor. The processor determines a travel time corresponding to travel of the substance between the first location and the second location using only the first data, the second data, and a constant. Preferably the processor does not require additional data relating to the sewer network or the substance.
Optionally, the method also includes the steps of detecting a first flow volume at the first location at a first time and detecting a second flow volume at the second location at a second time. The second time is a function of the first time and the travel time. The option also includes transmitting the first flow volume and the second flow volume to a processor. The processor determines a net flow corresponding to a difference between the second flow volume and the first flow volume.
Optionally, the determining step comprises divides the constant by either a sum or an average of the first data and the second data.
Optionally, the constant corresponds to or is determined by historic flow volume data for the first location and historic flow volume data for the second location over multiple time increments. As used herein, the word xe2x80x9chistoricxe2x80x9d does not imply any particular age, and can include the immediate past, even as close as a previous hour, minute, or second, as well as longer periods. To derive the constant, the method includes developing a distribution of first flow volume data from the first flow monitor over a period of time and a distribution of second flow volume data from the second flow monitor over a period of time. The constant corresponds to a goodness of fit test performed on the distributions.
As an additional option, the processor is integral with a flow meter that is located at either the first location or the second location.
In accordance with another embodiment of the present invention, a system for analyzing flow of a substance between a first location and a second location, includes a first meter capable of detecting a first flow velocity at a first location and a second meter capable of detecting a second flow velocity at a second location. The first meter and the second meter are in communication with a processor, and the processor is programmed to derive a travel time of a flow from the first location to the second location using the first flow velocity, the second flow velocity, and a constant. In a preferred embodiment of the present invention, no additional data relating to the flow or the locations are required.
Optionally, the first meter is also capable of detecting a first flow volume at the first location at a first time, the second meter is also capable of detecting a second flow volume at the second location at a second time. The second time corresponds to a sum of the first time and the travel time, and the processor is further programmed to determine a net flow based on the difference between the second flow volume and the first flow volume.
Optionally, the first location and the second location are locations within a sewer network. As a further option, the processor may be integral with the first or second meter.
In accordance with another embodiment of the present invention, a method of analyzing flow of a substance in a sewer network includes the steps of using multiple upstream flow meters to collect upstream flow volume data points corresponding to each upstream flow meter over a period of time, using a downstream flow meter to collect a downstream flow volume data point, and determining a travel time corresponding to travel of a substance between an upstream location corresponding to one of the upstream flow meters and a downstream location, the downstream location corresponding to the downstream flow meter, using the plurality of upstream flow volume data points, the downstream flow volume data point, and a constant, without requiring additional data relating to the sewer network or the substance. Optionally, the method also includes the steps of detecting a first flow volume at the upstream location at a first time, detecting a second flow volume at the downstream location at a second time that is a function of the first time and the travel time, and determining a net flow corresponding to a difference between the downstream flow volume and the upstream flow volume. In accordance with another embodiment of the present invention, a method of analyzing flow of a substance includes the steps of collecting a first set of flow volume data at a first location over a plurality of time increments, collecting a second set of flow volume data at a second location over a corresponding number of time increments, identifying a first distribution of the first set of flow volume data over time, identifying a second distribution of the second set of flow volume data over time, identifying a constant corresponding to a relation of the first distribution and the second distribution, detecting a first flow velocity at the first location, detecting a second flow velocity at the second location, and determining a transport time corresponding to a transport of a substance from the first location using the first flow velocity, the second flow velocity, and the constant, without requiring additional data. Optionally, the method also includes using the first flow meter at a first time, to detect an upstream flow volume, using the second flow meter at a second time being the sum of the first time and the transport time to detect a downstream flow volume, and calculating a net flow corresponding to a difference between the downstream flow volume and the upstream flow volume. Optionally, the relation in the identifying step comprises a goodness of fit test.
In accordance with an additional embodiment of the present invention, a method of analyzing flow of a substance in a sewer network includes the steps of using a plurality of upstream flow meters to collect a plurality of sets of upstream flow volume data corresponding to each upstream flow meter over a period of time, using a downstream flow meter to collect a set of downstream flow volume data over the period of time, identifying a plurality of upstream distributions corresponding to a set of upstream flow volume data over time, identifying a downstream distribution corresponding to the set of downstream flow volume data over time, identifying a constant corresponding to a relation of the upstream distributions and the downstream distribution, detecting a first flow velocity at an upstream location corresponding to one of the upstream flow meters, detecting a second flow velocity at a downstream location corresponding to the downstream flow meter, and determining a transport time corresponding to transport of a substance from the upstream location to the downstream location using the first flow velocity, the second flow velocity, and the constant, wherein the determining step does not require additional data. Optionally, the method also includes using a first flow meter at the first upstream location at a first time to detect an upstream flow volume, using the downstream flow meter at a time corresponding to a sum of the first time and the travel time to detect a downstream flow volume, and calculating a net flow corresponding to a difference between the downstream flow volume and the upstream flow volume. Optionally, the relation in the identifying step comprises a goodness of fit test.
There have thus been outlined the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form at least part of the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting in any way.
As such, those skilled in the art will appreciate that the concept and objectives, upon which this disclosure is based, may be readily utilized as a basis for the design of other structures, methods and systems for carrying out the several purposes of the present invention.